Ann M. Blair is an American historian, and Henry Charles Lea Professor of History at Harvard University.
She is most widely known for being the author of the bestselling book Too Much to Know: Managing Scholarly Information before the Modern Age.
Blair studied at Harvard University, the University of Cambridge and Princeton University. At Princeton, she was the first graduate student of Anthony Grafton. She defended a dissertation entitled 'Restaging Jean Bodin : the Universae Naturae Theatrum in its cultural context' in 1990, which became the basis of her 1997 book. Since 1996 she has taught at Harvard University.